problems while receving data from 8051 though gps

Hi,

i need help on receving data from the 8051 mircocontroller interfacing with GPS. currently, i m using printf and put char to transmit data to the GPS. But when i used scanf and printf for the data output. i found out that the data does not read the whole string data but one char. may i know where will b the problem lies? thanks..

void gps(void)
{
//Save Current SFR page
char SFRPAGE_SAVE = SFRPAGE;


g_uc_uart = 1;
printf("log version\r");
scanf("%s", g_s_gps_str);

printf("GPS %s", g_s_gps_str);

SFRPAGE = SFRPAGE_SAVE;
}

use a array to store the data being read.. Where are you displaying the result.... on terminal, or LCD.. post the complete code

Hi ckshivaram,

I managed to send a string data through the using interrupt base. But when i look into the memory of the interrupt, i could only see 6 characters have send through which i m sending about 31 characters. From the recieved data i could only see [COM1]................................... something similar to. Due to this is a school project i could not give you the whole code. I m using UART interrupt register to transmit the characters i send and then for the received part i using getkey function. May i know whether is it the interrupt of the way i send the commands is wrong? The method i send through is using for example: log version include with CF and LF.
thanks

could you connect GPS to PC serial port and check output on hyperterminal.... see if you get the output properly.

I tried it already. it does well when i connect to a PC serial port. But when i use the 8051 to send the commands, it somehow only receive 6 characters instead of 31 characters. Could it be the mircocontroller UART interrupt register could not receive the whole data or is there any way that i could receive the whole charcaters?
thanks

best regards
wei cheng

Which controller are you using make and manufacturer... see the data sheet on how much FIFO it has ( if it supports FIFO)

I m using sillicon lab mircontroller 8051. i went to check on the data sheets it seems like they do not have FIFO as you mention.

Iam using virtual distance measuring tape using gps with 8051
i need to read the data only latitude and longitude
iam getting so many other characters which i dont need on lcd

here is my code
#include <reg51.h> //Define 8051 Registers
#include <stdio.h>
#include <string.h> //Define I/O Functions
#define DATA P1 //Define DATA to Port1


#ifdef MONITOR51 /* Debugging with Monitor-51 needs */
char code reserve [3] _at_ 0x23; /* space for serial interrupt if */
#endif /* Stop Exection with Serial Intr. */
/* is enabled */

//Define control pins

sbit RS = P3^5; //Register Select
sbit RW = P3^6; //LCD Read/Write
sbit lcd_e = P3^7; //LCD Enable
unsigned char check;unsigned char utc; char active; char latitude[];
char lat_hem; char longitude[]; char lon_hem;
unsigned char temp; int n=0;
unsigned char buf[50];code unsigned char temp1; int p=0;code unsigned char longit[50];unsigned char data2;


//----------------------------------
// LCD Functions
//----------------------------------
//void lcd_cmd(unsigned char);
//void lcd_display(unsigned char);

void DelayMs(int);


//----------------------------------
// LCD command Function
//----------------------------------
void lcd_cmd(unsigned char cmnd)
{
DATA = cmnd;
RS = 0;
RW = 0;
lcd_e = 1;
DelayMs(35);
lcd_e = 0;
}


//----------------------------------
// LCD Data Function
//----------------------------------
void lcd_display(unsigned char dat)
{
DATA = dat;
RS = 1;
RW = 0;
lcd_e = 1;
DelayMs(35);
lcd_e = 0;
}



//----------------------------------
// LCD Delay Function
//----------------------------------
void DelayMs(int k)
{
unsigned int a;
for(a=0;a<=k;a++);
}



//----------------------------------
// LCD Initialization
//----------------------------------
void lcd_init(void)
{
unsigned char i;
unsigned char j;
lcd_cmd(0x38); //2x16 Character 5x7 dot
DelayMs(15); //matrix LCD,8-bit format
lcd_cmd(0x0c); //Display On, cursor off
DelayMs(15);
lcd_cmd(0x06); //Shift Cursor to right
DelayMs(15);
lcd_cmd(0x01); //Clear display screen
DelayMs(15);


//-------------------------------------------
// First Line Message Display
//-------------------------------------------
lcd_cmd(0x80); //First Line Initialization
DelayMs(35);
i=0;
while(buf!='\0')
{
lcd_display(buf);
i++;
}
DelayMs(50);
//second line
/* lcd_cmd(0xc1);
DelayMs(35);
while(longit[j]!='\0')
{
lcd_display(longit[j]);
j++;
} */

while(1);
}



//----------------------------------
// LCD Main Program
//----------------------------------
void main(void)
{

while(1)
{
#ifndef MONITOR51
SCON = 0x50; /* SCON: mode 1, 8-bit UART, enable rcvr */
TMOD |= 0x20; /* TMOD: timer 1, mode 2, 8-bit reload */
TH1 = 0XFD; /* TH1: reload check for 1200 baud @ 16MHz */
TR1 = 1; /* TR1: timer 1 run */
TI = 1; /* TI: set TI to send first char of UART */
#endif

check= scanf("%c",&check);
if(check='$')
{ check=scanf("%c",&check);
if(check='G')
{ check=scanf("%c",&check);
if(check='P')
{ check=scanf("%c",&check);
if(check='R')
{ check=scanf("%c",&check);
if(check='M') { check=scanf("%c",&check);
if(check='C') { check=scanf("%c",&check);
if(check=',')
{
do
{
scanf("%c", &temp );
}
while(temp!=',') ;
check=scanf("%c",&temp);
if(check='A') {
do{
scanf("%c", &temp); }
while(temp!=',');

do
{ scanf("%c", &temp);
sprintf(buf+n,"%c", temp); n=n+1; }
while(temp!=',');
do{
scanf("%c", &lat_hem); }
while(lat_hem!=',');
do
{ scanf("%c", &data2);
sprintf(buf+n,"%c",data2);n=n+1;
}
while(data2!=',');
}

} }}}}}


lcd_init(); //LCD Initialization
DelayMs(50);
}}}




please reply..........................
thank u